EP2436019A1

EP2436019A1 - Method for attaching a continuous strand to a substrate and strand thus obtained

Info

Publication number: EP2436019A1
Application number: EP10723070A
Authority: EP
Inventors: Joseph Leibenguth; François Roussel
Original assignee: Gemalto SA
Current assignee: Thales DIS France SA
Priority date: 2009-05-29
Filing date: 2010-05-20
Publication date: 2012-04-04
Also published as: WO2010136382A1; EP2256759A1

Abstract

The invention relates to a method for attaching a continuous strand (3) to a substrate (4) following a predetermined path, said path comprising linear portions (L), inflexion areas (Z) bordering said linear portions and points (PF) for attaching the strand to the substrate separated by a pitch (P1, P2). The method is characterised in that it comprises the step of adjusting the pitch (P1, P2) from one linear portion to the next according to the length (L1, L2) of each portion such that said inflexion areas (Z) correlate with said attachment points (PF). The invention also relates to the strand obtained and to an electronic product including the strand.

Description

Method for fixing a continuous thread on a substrate and wire thus obtained

The invention relates to a method of fixing a continuous wire on a substrate in a predetermined path and the wire thus obtained.

More particularly, the invention relates to wire paths comprising linear portions, zones of inflection bordering these linear portions and points for fixing the wire on the substrate spaced apart by a pitch corresponding to the pitch of a tool. of fixation .

The invention finds particular application to the realization of contactless smart card and / or travel document such as electronic passport, electronic visa, electronic tag, any electronic communication product having a wire antenna connected to an electronic component.

Different techniques exist for the manufacture of antennas for radio frequency applications (smart card, passport, contactless communication objects).

The main techniques make it possible to obtain engraved antennas printed by screen printing, inlaid by thermal or ultrasonic probe, prebobinated and then transferred to a substrate or embroidered.

All of these solutions are either technically limited: conductivity limitation for the printed antenna for example, difficulty of handling for the coil antenna, high cost for the engraved antenna, difficulty of handling for embroidered fabric. In addition, the cost resulting from the antenna remains relatively high compared to the raw material used and the supports are not always well adapted to the intended use.

The invention aims to solve the aforementioned drawbacks.

The object of the invention is first of all to provide a flexible method of manufacturing an antenna adapted to the final device whatever the nature of the substrate.

The invention also aims to considerably increase the speed of fixing or removing the wire on a substrate, by providing flexibility in the choice of the substrate.

The principle of the invention consists in a preferred mode of unwinding an antenna wire quickly between remarkable areas of inflection of the antenna on a substrate and to fix this wire to these remarkable areas and preferably only to these areas.

According to a preferred feature, the substrate is prepared to receive or facilitate the reception of all or part of the wire in the thickness of the substrate. The preparation may concern points or zones of yaw inflection only and / or zones continuous or discontinuous on the future course of the wire between two inflection zones.

For this purpose, the subject of the invention is a method of fixing a continuous wire on a substrate along a predetermined path, said path comprising linear portions, zones of inflection bordering these linear portions and points for fixing the wire. on the substrate spaced one step apart; The method is characterized in that it comprises the step in which the pitch between the thread fixing points is adjusted from one portion to the other according to the respective lengths of each linear portion so that said zones of inflection correspond with said fixing points.

With these provisions, the invention is much faster to deposit a wire on a substrate.

According to other features: the fastening points comprise perforations in the substrate, the thread being held at least partly in each perforation, thus making it possible to house fastening means, in particular sewing holding thread, solder ball, drop of glue ... thus making it possible to fix the wire on a wide variety of substrate materials; the method comprises the production of at least one groove, said groove extending between said points and in the thickness of the substrate, partially or totally, so as to accommodate at least partially the wire, thus making it possible to retract the thickness of the conductor wire or other means of holding wire or fixing.

The method is preferably applied to the realization of radiofrequency antenna on a substrate, but it can be used as appropriate to any electrical or conductive wire or not.

It allows in particular the production of electronic product constituting a radiofrequency communication object, such as a contactless smart card, a passport in which the circuit is an antenna circuit.

The invention also relates to a continuous wire on a substrate in a predetermined path, said path comprising linear portions, inflection zones bordering these linear portions and wire attachment points on the substrate spaced a step. The yarn is distinguished in that the pitch between thread attachment points is adjusted from one portion to the other as a function of the respective lengths of each linear portion so that said inflection zones correspond with said yield points. fixation.

According to one characteristic, the conductive wire comprises linear portions whose attachment points are spaced at least 1.4 cm, 2 cm or 4 or 5 cm or more. It will be understood that the invention makes it possible to quickly fix a radiofrequency transponder antenna conductor wire as soon as to the machine to have a step much more important than that used to date. Today, this step is fixed and limited to 2 mm over the entire course of an antenna wire. On the other hand, the corners of the antennas formed by embroidery are rounded in particular to respect the inter-turn space of the antenna which can be smaller than 2 mm, in particular 0.5 mm.

According to another characteristic, the conductive wire comes into contact with at least two attachment points, each located at a point of inflection, but to improve the hold and the spacing of the turns during the production of an antenna by for example, the attachment points will be spaced with a variable pitch. This step can range from 5 mm to 5 cm.

As soon as the length of the portion of thread to be fixed allows (long straight line), the fastening machine can move to a step and / or a greater speed of movement. This variable pitch on a portion or between juxtaposed portions is also a characteristic of the capacity of the invention.

Other features and advantages of the invention will appear on reading the description which follows, given by way of illustrative and nonlimiting example, and with reference to the appended figures for which:

- Figure 1 illustrates a schematic view of a transponder being formed according to a path arrow and according to a preferred embodiment of the method of the invention; - Figure 2 illustrates a sectional view along AA of Figure 1;

- Figure 3 illustrates a sectional view along A-A of Figure 1 according to a first implementation variant;

- Figure 4 illustrates a sectional view along A-A of Figure 1 according to a second implementation variant.

In FIG. 1, an electronic product 1 according to the invention comprises an electrical circuit comprising a conducting wire 3. The electronic product here constitutes a radiofrequency communication object, such as a contactless smart card, a passport in which the circuit is an antenna circuit.

The wire is continuous conductor and extends over a substrate 4 in a predetermined path, here in the form of a flat spiral to form a radio frequency transponder antenna; The path comprises linear portions (here portions of three turns parallel to each side of the rectangular substrate); It also comprises points or zones of inflection (Z) or change of direction bordering these linear portions (L) and fixing points (PF) of the wire on the substrate spaced apart by a pitch P1, P2, ...

The wire can be isolated or not by an insulating sheath, a varnish. The wire in the figure is in formation as seen by the arrows on each portion of wire 3 which also indicates the path followed by the wire to form the antenna circuit. It will be considered for the sake of simplicity that the arrow path also defines a wire of a formed antenna.

According to one characteristic of the invention, the pitch P1, P2 for fixing the wire is adjusted from one portion L1 to the other L2 as a function of the respective lengths of each linear portion so that the said fixing points correspond with the inflection zones (Z).

The adjustment can be made especially on the fly according to a calculation program and / or VAO or for example be preprogrammed in advance to preset values.

This is specified in opposition to sewing or embroidery in particular for which the step is fixed on a course or at least in the middle of a course. And in general, the pitch is identical from one linear portion to another subsequent linear portion.

The invention consists in considerably increasing the pitch P1, P2 of fixing up to correspond to the maximum length L1, L2 of the portions. As soon as the rectilinear length of the course allows it, the pitch is likely to be lengthened to go fast (like the vehicle speed reports). In a slightly slower mode, the pitch P1, P2 may comprise one point or several intermediate points depending on the length of the portions. For linear portions less than 2 cm, or even 3 or 4 cm, it is not useful in principle to have intermediate fixing points, the wire being well held.

Generally for a map substrate, the largest portion can measure about 6 - 9 cm and the small portion 3-6 cm. The fixing bridges are spaced apart by more than 2 cm, or even 4 or 5 cm.

Normally sewing or embroidery applied to the formation of conductive antenna, the pitch may include a normal pitch of an amplitude of a few millimeters (about 2mm-2.5mm). Preferably, all or almost all the intermediate steps of this amplitude are suppressed on the same linear portion because they reduce correspondingly the speed of fixation.

Thus, the invention provides jumps from one angle to another of a path or conductive circuit. These jumps are generally greater than 2 cm on linear portions greater than 2 cm.

As can be seen more specifically in FIG. 2, according to a preferred embodiment, the fixing points PF comprise or each constitute a perforation in the substrate. The perforation is partial through the thickness of the substrate 4 but it could open on both sides. In Figure 3, according to one embodiment, the substrate has grooves or grooves 5 on the path and between the fixing points PF. These grooves are intended to house all or part of the thickness of the continuous conductive wire deposited on the substrate during the formation of the antenna circuit.

In Figure 4, according to one embodiment, grooves or grooves 5 are disposed on either side of the substrate. This makes it possible to accommodate, if necessary, a bottom or bobbin thread for attachment by sewing or embroidery. PFT perforations pass through the substrate.

A preferred embodiment of the method for producing the transponder of FIG. 1 is described below.

According to one embodiment, the method of fixing a continuous conductive wire on a substrate in a predetermined path comprises the step in which the pitch of the wire is adjusted from one portion to another according to the lengths respective linear portions so that said attachment points correspond with said inflection zones.

Provided according to the invention a fixing of a first point of wire at a first fixing means F of the substrate (starting point 9), then a linear guide of a portion L of wire and fixing a second point of thread at the level of a second point or means of attachment to the substrate. And so on to the end point 8.

According to a first mode of implementation, the support comprises sighting marks or marks of a tool or fastening head of a fixing machine. The head moves while being controlled by an internal program of displacement corresponding to the antenna path, preset and stored in an internal memory of the fixing machine.

According to an alternative of moving the fastening tool, a program in a fastening machine implements steps of variation of the fastening step as a function of the linear length of the linear portion. The larger the portion, the more the step will tend to be large.

The machine also comprises a detection system fixing points previously made on the substrate. It can be a computer-assisted vision system or equivalent (VAO). The step is determined on the fly by the machine.

A machine controller controls the fastening heads to position themselves on the fastening points. The attachment pitch is then changed according to program data or coordinates of all attachment points to accommodate the different length of subsequent portions. When a portion length Ll, L2 is less than a limit step imposed on the machine, the fastening pitch equals this length. If not, the machine jumps directly to the next attachment point if it is at a distance less than a machine pitch limit.

The pitch of fixation can reach a limit in length due to technical constraints. In this case, the linear portion may be optionally split into several substantially homogeneous portions.

When a portion length is greater than a machine limit, the length can be split into portions smaller than the maximum pitch.

In the example illustrating the method, the fixing points or means comprise perforations (F) in the substrate, the wire is maintained at least partly in each perforation. However, other points or equivalent means are also contemplated by the invention:

Metal islands prefixed to the substrate for receiving the wire;

Glue islands pre-deposited on the substrate for receiving the wire;

- Perforations or blind holes cylindrical or conical to "stuck" the wire.

In the third alternative, the machine comprises a multiple head (comprising for example a laser tool, a placement tool) that cleans the points and / or grooves just before placing the wire in it. Thus the course is followed only once by a machine.

More specifically, the multiple head is positioned above the first point 9 (or inflection zone Z), a PF perforation is formed and then the wire is fixed in, then the wire is unwound in the direction of the future point of inflection following where the tool is positioned before making another PF perforation and fix in the tensioned wire and so on.

In an advantageous variant, the method comprises producing at least one groove between the attachment points; the groove extends between said points and in the thickness of the substrate, partially or totally, so as to accommodate at least partially the wire or facilitate its housing for example by subsequent lamination.

The fixing of the thread can be done by an embroidery technique or sewing or equivalent;

The securing operation may include introducing a needle with a portion of wire into said perforation. The conductive thread may be formed in the manner of sewing overcasting or by embroidery with holding by a bobbin thread.

The perforations or grooves may be performed according to a technique chosen from laser engraving, machining, stamping, thermoforming, sandblasting.

Regarding the multi-head machine and in the case of the use of grooves, they can be made just before the wire is unrolled in, the laser tool (or equivalent) being always moved by the same multiple head supporting the placement tool.

We now describe a practical mode of implementation of the method which takes into account current technological constraints.

The basic concept of the invention first makes it possible to choose a substrate which is the most suitable for the manufacture of a final device without contact: for example the substrate may be of the thermoplastic type such as PVC, polycarbonate, or known synthetic paper. under the name of "Teslin".

The support is not limited to a thin fabric or a support accepting a heat or ultrasonic sink such as thermoplastics (PVC, Teslin ...). Hard or rigid materials such as glass, wood, paper, metal, pre-formed or perforated printed circuit boards may be considered.

In a second step a CO ² laser or drilling device (as used in the PCB industry) drills holes in

"Edge" or "angle" PF representing the future shape of the antenna.

Finally, the copper wire will be unwound from one PF hole to the other and secured to the inside of each hole with a standard sewing process. An alternative solution would be to add some grooves also milled or etched to drive the copper wire into the substrate.

This invention can be used to make an insert or inlay, the cover or the electronic page of a passport. It is generally accepted that polycarbonate is a good substrate for the manufacture of electronic pages (eDatapage) for the passport.

With the invention, it will be possible to manufacture an electronic page in a homogeneous manner with only the use of the polycarbonate material

(without an intermediate substrate, especially with a fabric base).

The central portion of the electronic page may consist for example of a thin layer of polycarbonate of 50 .mu.m.

This layer would first be laser drilled and possibly etched later before the copper wire is sewn on or inside.

The next step consists in producing a cavity 7 for receiving an electronic module comprising a non-contact electronic chip (not shown).

Then, the electronic module, usually supplied in coil format, is punched out of the leadframe film and placed in the cavity referred to above and connected by thermo compression, welding or equivalent techniques at both ends of the antenna wire (8, 9).

The insert (or inlay) thus produced will be assembled with other polycarbonate sheets (front and back and / or compensation layers) and laminated with these sheets to form the electronic page.

A similar process can be applied to the manufacture of contactless smart cards generally made in sheet form (mainly using PVC plastic) but also to electronic passport covers for which the most used material is synthetic paper called Teslin.

The main advantages of this invention are:

- Reduction of costs by simplifying the machine for fixing the wire (wiring or stitching) and increasing the productivity due to the absence of an operation of pressing the wire by ultrasound, by heat or by fixing via a stitching or embroidery traditionally working with a reduced pitch of a few millimeters in a few millimeters, as well as by reducing the number of attachment points.

Compatibility of the method with a wide variety of substrate materials that makes it possible to use the same substrate as that most commonly used to date for non-contact devices. Alternative solutions or enhancements may include:

- Providing portions of the substrate with holes and grooves already molded; use of gold-based fastening technology as an alternative to sewing (eg capillary, "sparkle" to produce a wire lock ball in a hole, solder ball embedded in a hole, etc.)

Claims

1. A method of fixing a continuous wire (3) on a substrate (4) in a predetermined path, said path comprising linear portions (L), inflection zones (Z) bordering these linear portions and points of contact. fixing (PF) of the wire on the substrate spaced apart by one step (P1, P2), characterized in that it comprises the step according to which the pitch (P1, P2) is adjusted from one linear portion to the other as a function of the lengths (L1, L2) of each portion so that said inflection zones (Z) correspond with said fixing points (PF).

2. Method according to the preceding claim, characterized in that said attachment points (PF) comprise perforations (10) in the substrate, the wire being maintained at least partly in each perforation.

3. Method according to one of the preceding claims, characterized in that it comprises the production of at least one groove (4, 5), said groove extending between said points (PF) and in the thickness of the substrate. , partially or totally, so as to accommodate at least partially the wire.

4. Method according to any one of the preceding claims, characterized in that the fixing of the thread is performed by an embroidery technique or stitching or equivalent, the operation of fastener comprising inserting a needle and a portion of thread into said perforation.

5. Method according to any one of the preceding claims, characterized in that the perforations or grooves are performed according to a technique chosen from laser engraving, machining, stamping, thermoforming, sandblasting.

6. Application of the method according to any one of the preceding claims to the realization of radiofrequency antenna on a substrate or an electrical circuit.

7. Continuous conductor wire on a substrate (4) according to a predetermined path, said path comprising linear portions (L), inflection zones (Z) bordering these linear portions and fixing points (PF) of the wire on the substrate spaced apart by one step (P1, P2), characterized in that the pitch is adjusted from one portion to the other according to the respective lengths (L1, L2) of each linear portion so that said zones Inflection (Z) correspond with said attachment points (PF).

8. Conductor wire according to the preceding claim, characterized in that the fixing points (PF) each comprise a perforation (10) in the substrate.

9. Conductive wire according to any one of claims 7 to 8, characterized in that portions contain attachment points spaced at least 1.4 cm or 4 or 5 cm.

10. Conductive wire according to any one of claims 7 to 9, characterized in that the wire maintained by a sewing process or embroidery.

11. An electronic product comprising an electrical circuit comprising the conductive wire according to any one of claims 7 to 10 or obtained according to the application of claim 6.

12. Electronic product according to the preceding claim constituting a radiofrequency communication object, such as a contactless smart card, a passport in which the circuit is an antenna circuit.